1. Structural Biology and Molecular Biophysics
  2. Cell Biology

Structural basis for activation, assembly and membrane binding of ESCRT-III Snf7 filaments

  1. Shaogeng Tang
  2. W Mike Henne
  3. Peter P Borbat
  4. Nicholas J Buchkovich
  5. Jack H Freed
  6. Yuxin Mao
  7. J Christopher Fromme
  8. Scott D Emr  Is a corresponding author
  1. Cornell University, United States
  2. The University of Texas Southwestern Medical Center, United States
  3. The Pennsylvania State University College of Medicine, United States
https://doi.org/10.7554/eLife.12548
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Cite this article
  1. Shaogeng Tang
  2. W Mike Henne
  3. Peter P Borbat
  4. Nicholas J Buchkovich
  5. Jack H Freed
  6. Yuxin Mao
  7. J Christopher Fromme
  8. Scott D Emr
(2015)
Structural basis for activation, assembly and membrane binding of ESCRT-III Snf7 filaments
eLife 4:e12548.
https://doi.org/10.7554/eLife.12548
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Abstract

The endosomal sorting complexes required for transport (ESCRTs) constitute hetero-oligomeric machines that catalyze multiple topologically similar membrane-remodeling processes. Although ESCRT-III subunits polymerize into spirals, how individual ESCRT-III subunits are activated and assembled together into a membrane-deforming filament remains unknown. Here, we determine X-ray crystal structures of the most abundant ESCRT-III subunit Snf7 in its active conformation. Using pulsed dipolar electron spin resonance spectroscopy (PDS), we show that Snf7 activation requires a prominent conformational rearrangement to expose protein-membrane and protein-protein interfaces. This promotes the assembly of Snf7 arrays with ~30Å periodicity into a membrane-sculpting filament. Using a combination of biochemical and genetic approaches, both in vitro and in vivo, we demonstrate that mutations on these protein interfaces halt Snf7 assembly and block ESCRT function. The architecture of the activated and membrane-bound Snf7 polymer provides crucial insights into the spatially unique ESCRT-III-mediated membrane remodeling.

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Author details

  1. Shaogeng Tang

    Weill Institute of Cell and Molecuar Biology, Cornell University, Ithaca, United States
    Competing interests
    The authors declare that no competing interests exist.

  2. W Mike Henne

    Department of Cell Biology, The University of Texas Southwestern Medical Center, Dallas, United States
    Competing interests
    The authors declare that no competing interests exist.

  3. Peter P Borbat

    National Biomedical Center for Advanced Electron Spin Resonance Technology, Cornell University, Ithaca, United States
    Competing interests
    The authors declare that no competing interests exist.

  4. Nicholas J Buchkovich

    Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, United States
    Competing interests
    The authors declare that no competing interests exist.

  5. Jack H Freed

    National Biomedical Center for Advanced Electron Spin Resonance Technology, Cornell University, Ithaca, United States
    Competing interests
    The authors declare that no competing interests exist.

  6. Yuxin Mao

    Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, United States
    Competing interests
    The authors declare that no competing interests exist.

  7. J Christopher Fromme

    Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, United States
    Competing interests
    The authors declare that no competing interests exist.

  8. Scott D Emr

    Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, United States
    For correspondence
    sde26@cornell.edu
    Competing interests
    The authors declare that no competing interests exist.

Copyright

© 2015, Tang et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Shaogeng Tang
  2. W Mike Henne
  3. Peter P Borbat
  4. Nicholas J Buchkovich
  5. Jack H Freed
  6. Yuxin Mao
  7. J Christopher Fromme
  8. Scott D Emr
(2015)
Structural basis for activation, assembly and membrane binding of ESCRT-III Snf7 filaments
eLife 4:e12548.
https://doi.org/10.7554/eLife.12548

Share this article

https://doi.org/10.7554/eLife.12548

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    1. Biochemistry and Chemical Biology
    2. Cell Biology

    ESCRT-III activation by parallel action of ESCRT-I/II and ESCRT-0/Bro1 during MVB biogenesis

    Shaogeng Tang, Nicholas J Buchkovich ... Scott D Emr
    Research Advance Updated

    The endosomal sorting complexes required for transport (ESCRT) pathway facilitates multiple fundamental membrane remodeling events. Previously, we determined X-ray crystal structures of ESCRT-III subunit Snf7, the yeast CHMP4 ortholog, in its active and polymeric state (Tang et al., 2015). However, how ESCRT-III activation is coordinated by the upstream ESCRT components at endosomes remains unclear. Here, we provide a molecular explanation for the functional divergence of structurally similar ESCRT-III subunits. We characterize novel mutations in ESCRT-III Snf7 that trigger activation, and identify a novel role of Bro1, the yeast ALIX ortholog, in Snf7 assembly. We show that upstream ESCRTs regulate Snf7 activation at both its N-terminal core domain and the C-terminus α6 helix through two parallel ubiquitin-dependent pathways: the ESCRT-I-ESCRT-II-Vps20 pathway and the ESCRT-0-Bro1 pathway. We therefore provide an enhanced understanding for the activation of the spatially unique ESCRT-III-mediated membrane remodeling.